Buffy Sainte-Marie ... her voice is as robust as ever. Photograph: David Levene

All gushing jet black hair, radiant smiles and shining eyes, Buffy Sainte-Marie looks fabulous. "Do I? Why thank you …" She seems shocked. She's 67 and has dived into London between gigs in Norway and Ontario and isn't entirely sure what day it is. She certainly has no clue what time it is. But, aided by caffeine, she's swiftly into her stride, vigorously debating the colourful contours of her extraordinary life – from Native American rights campaigner and protest music icon to hit songwriter, amateur astrologer, teaching co-ordinator and electronic music pioneer. Glorious anecdotes tumble in rapid succession: writing Universal Soldier to impress her college professor; hanging out with Muhammad Ali, Marlon Brando and Jane Fonda; shocking middle America by breastfeeding her baby son Cody on the TV show Sesame Street; hitting the campaign trail with Barack Obama; fighting off Elvis Presley's "people" when they tried to pressurise her into relinquishing the publishing rights to Until It's Time for You to Go; the joys of living on a farm in Hawaii; reading her own FBI file; helping to launch Joni Mitchell's career; and being blacklisted by the Johnson and Nixon administrations.

"Do you know," she says, "my album Coincidence & Likely Stories in 1991 was the first ever delivered via the internet and the Guardian did a big story on it with a picture? People didn't want to know about electronic music or digital or any of that then, but you were the first paper in Europe to write about the early use of the internet in that way. You guys were hip way back then." Aw, thanks Buffy – and you still look fabulous.

But we haven't seen or heard much of Buffy Sainte-Marie since then. In the UK, in fact, we haven't seen anything of her. She's been busy, she says. Doing other stuff. Like setting up the Cradleboard Teaching Project, her cultural study programme for Native Americans, which was awarded a major grant by the Kellogg Foundation in 1996 and which has consumed her ever since. "It really started in the 60s when I was just a young singer with too much money and I had all these aeroplane tickets. They're the link to my whole existence because they've enabled me to travel. And if I have a concert in Stockholm, it means I can visit the aboriginal people in the Arctic. Or if I'm playing in Melbourne or Sydney, I'll go out and visit the aboriginal people in the Bush. The Cradleboard Project is a result of my experiences living in two worlds – the fancy showbusiness world of hotels and aeroplanes – and spending time with interesting people who have a lot to say. I'm a bridge – Cradleboard helps connect people in indigenous communities with the rest of the world."

At last she's back for her first UK appearances in the best part of two decades, promoting Running for the Drum, her first album of original material since Coincidence & Likely Stories. "I didn't fall out of love with music," she says. "In fact I'm always writing and recording, but there's no sense in putting out an album unless you're going to be in the music business and tour, and I just didn't have time. But I had these songs and I was kinda hot to go on the road again."

For anyone anticipating either the impassioned folk songs with which she initially made her name or the more lucrative romantic pop of Up Where We Belong, Running for the Drum may come as a shock. Her voice is as robust as ever – that famous vibrato intact - and the thunderous chants that drive the first two tracks, No No Kesahagesh and Cho Cho Fire, would challenge the energy levels of someone a third of her age. She's clearly also been having fun with the computer. "Computers always felt natural to me. When the Macintosh came out in 1984, it was heaven. It meant I could do my paintings, my music and my writing all on the same machine."

The new album also includes the old patriotic song America the Beautiful, rewritten as a tribute to her Native American heritage and which she first sang at the launch of the space shuttle Endeavour in 2002 when a Chickasaw, Commander John Herrington, become the first Native American in space. "I see the US as the poor abused child of politicians and corporate mentalities," she says, "but it's full of hope and talent and creativity and every now and then someone will open the drapes and allow the sunshine in."

Sainte-Marie is a Cree from Saskatchewan who, while tirelessly fighting for Native American rights, has also fiercely resisted the white liberal inclination towards pity and the "Pocahontas plays guitar" stereotype the media tried to nail on her. "When I wrote Now That the Buffalo's Gone I felt that if white people knew of the plight of contemporary Native American people they'd help, and to some extent they did, but to a bigger extent they didn't. It was just a song that made people say, 'Oh let's go and see the little Indian girl who makes us cry.' So I recorded things like Indian Cowboy in the Rodeo because I was interested in shining a spotlight on the beauty of the people I saw at home. Yes, there were sorrowful things. Yes, there are tragedies. But there are [also] triumphs and beauties."

She also wrote the theme song for Soldier Blue, the brutal movie graphically depicting the massacre of a Cheyenne village by Colorado State Militia, which, you fondly imagine, might have marked a sea-change in public opinion about how the west was won. "It sure was," she spits, bitterness in her voice for the first and only time, "it drowned a whole bunch more Indian voices. No-one knows Soldier Blue in North America. I can guarantee you won't find three people in the US who know it. It was taken out of the theatres after a few days." Why? "Why? What year did Soldier Blue come out? 1970? Oh, that'll be Richard Nixon."

This short, sharp outburst apart, she's remarkably sanguine about being investigated by the FBI and CIA and being blacklisted for her anti-Vietnam and pro-Native American rights work. "It affected my career but it didn't affect my life. It was all done in total secrecy. It's not like they tell you they're gonna deny your rights or trample your freedom or gag you – they just do it."

Innocent and naive, she sold the publishing rights to Universal Soldier for a dollar to a man she met one night at the Gaslight Cafe in Greenwich Village who wrote a contract on a napkin ("Ten years later I bought it back for 25,000 bucks – the good news is that I had 25,000 bucks.") Yet she still talks in awe of that period when the protest song ruled and the enemy was war. "Forget the singers and songwriters, it was a student movement, a very real thing. Those kids didn't want to be drafted and go to Vietnam for some businessman. Kids aren't that smart these days. Now they go to Iraq for some businessman. It was a different time. The music came from something real going on in the street and the drug was caffeine. We didn't know if we could change the world but we were gonna try. They tried to gag us but it couldn't be done. Can music and student power make any difference? Well, that war came to an end and that generation had a lot to do with it."